Counterbalancing chassis for aerial platform apparatus

ABSTRACT

An aerial platform apparatus includes a chassis supported by wheels, the chassis carrying centrally thereof a boom support revolvable on a vertical axis. A boom carried by the boom support carries a load at its outer end. The chassis is rectangular in plan form, having a pair of transversely spaced, longitudinally extending chassis members which are each unitary, rectangular in vertical cross section and of a thickness greater than required to resist strains to thereby provide an integral counterweight and chassis member.

United States Patent [191 Grove Jan. 21, 1975 COUNTERBALANCING CHASSISFOR AERIAL PLATFORM APPARATUS [75] Inventor: John L. Grove,McConnellsburg,

Fulton Industries, Inc., McConnellsburg, Pa.

22 Filed: July 13, 1973 21 App]. No.: 379,151

[73] Assignee:

[52] US. Cl. 182/141, 182/2, 280/106 R [51] Int. Cl B66f 11/04 [58]Field of Search 182/2, 63, 141; 280/106 R [56] References Cited UNITEDSTATES PATENTS 1,676,342 7/1928 Mackenzie 280/106 R 2,144,760 1/1939Harnischfeger 280/106 R 2,804,984 9/1957 Ulinski 280/106 R 5 ll 24 20b2,842,378 7/1958 Way 280/106 R 3,191,716 6/1965 Eitel 182/2 3,622,17811/1971 Tantlinger 280/106 T Primary ExaminerReinaldo P. MachadoAttorney, Agent, or Firmlrvin A. Lavine [57] ABSTRACT An aerial platformapparatus includes a chassis supported by wheels, the chassis carryingcentrally thereof a boom support revolvable on a vertical axis. A boomcarried by the boom support carries a load at its outer end. The chassisis rectangular in plan form, having a pair of transversely spaced,longitudinally extending chassis members which are each unitary,rectangular in vertical cross section and of a thickness greater thanrequired to resist strains to thereby provide an integral counterweightand chassis member.

7 Claims, 4 Drawing Figures COUNTERBALANCING CHASSIS FOR AERIAL PLATFORMAPPARATUS BACKGROUND OF THE INVENTION The present invention relates to aconstruction of the chassis of an apparatus having a boom, such as anaerial platform apparatus, or a crane.

Cranes have long been used to lift a load at one location, to move itand then deposit it at another location, these cranes including a boomhaving a load supporting cable depending from the outer end thereof. Thecranes having conventionally been constructed so that the boom could beraised and lowered, as well as rotated about a vertical axis. It is alsoknown to provide such cranes on a mobile chassis, so that they may bemoved from place to place.

There have also been provided aerial platform apparatus, which were tosome extent similar to cranes, in that they included a mobile chassis,typically mounted on three or four supporting wheels, a boom pivoted ona horizontally extending pivot so that it could be raised and lowered,the boom carrying at its outer end a platform or basket in which aworkman was positioned. Typically, such aerial platforms permit turningmovement of the boom about a vertical axis, and the boom itself isextensible. Consequently, the workmans platform could be placed at manydifferent positions, due to the rotation of the boom about a verticalaxis, its rotation about a horizontal axis and its extensibility alongits length.

It has been recognized in connection with both cranes and aerialplatforms that when the boom is positioned so that it is substantiallytransverse to the longitudinal axis of the vehicle or chassis whichsupports it, is extended its greatest amount, and is as close aspossible to the horizontal, there is generated the greatest tippingmoment, for a given load or weight supported at the end of the boom. Tocounteract this tipping moment, cranes are generally provided with alarge counterweight on the rotating boom support structure, on theopposite side of the axis of rotation from the boom, and are alsoprovided with extensible outriggers. These measures, including theoutrigger, have proven to be satisfactory in connection with cranes,since cranes are relatively fixed at a particular work location.However, in the case of aerial platform apparatus, the use of outriggersis not satisfactory in many instances, such as when the workman on theaerial platform performs tasks of brief duration at locations which areso spaced that it is required that the entire apparatus be moved toenable the workman to have access to each location.

Heretofore, in connection with aerial platform apparatus where the boomreach was up to about sixty feet, the chassis had been made of rolledsteel sections, such as I-beams, C-channels and T-bars. Thencounterweights were added to the chassis, such as by being bolted tolongitudinally extending chassis members made of I-beams. These added oncounterweights have been found, however, to increase the cost ofproduction of such machines, and, in addition, created a structure whichcould be hazardous, since it was possible for a workman to place his legbetween the counterweight and another part of the structure, with dangerof injury.

SUMMARY OF THE INVENTION An aerial platform apparatus is providedincluding a chassis supported by ground engaging wheels, the chasbers,and front and rear transverse members, there being four wheels supportedby the transverse members. A ring element is supported with its centerat the center line of the chassis, equally distant between the twolongitudinally extending members, and on this ring there is journalled aboom support structure which may be rotated through at least on thevertical axis extending through the ring. The boom support structureincludes a horizontal pivot which carries the boom, and the boom ispreferably extensible, carrying at its outer end a workmans platform orbasket. The chassis is characterized by a pair of laterally spaced andlongitudinally extending integral chassis members and counterweights.Each of these chassis members is formed of a slab of metal which is ofrectangular cross section in the vertical plane, with the long side ofthe rectangle extending vertically. These longitudinally extendingintegral chassis members and counterweights may have other chassismembers secured to them, as by welding, and may have discontinuities,such as openings. However, they are characterized by being ofsubstantially greater dimensions than would be required for normalstress considerations.

Among the objects of the present invention are to provide an aerialplatform apparatus including a chassis which is counterweighted tocounteract sidewise tipping.

Another object of the present invention is to provide an aerial platformapparatus having an integral chassisstrut which is more economical tomanufacture than previously manufactured chassis.

Still another object of the present invention is to provide a chassisfor an aerial platform apparatus having integral chassis members andcounterweights.

Other objects and many of the attendant advantages of the presentinvention will be more readily understood from the followingspecification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of anaerial platform apparatus in accordance with the present invention.

FIG. 2 is a plan view of the chassis of the apparatus of FIG. 1,generally taken on the line 2-2 of FIG. 1.

FIG. 3 is a side elevation of the chassis shown in FIG. 2.

FIG. 4 is a cross sectional view taken on the line 4-4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,wherein like or corresponding reference numerals are used to designatelike or corresponding parts throughout the several views, there is shownin FIG. 1 an aerial platform apparatus generally designated 10,including a pair of front wheels 12 and 12', carried by a chassis 14.Chassis 14 carries a boom support structure 16, which is rotatablethereon about vertically extending axis A. Boom support structure 16includes a horizontal pivot 18, which pivotally supports a boom 20.Preferably, boom 20 is an extensible boom including a base section 20a,a midsection 20b and a fly sectison 20c, each being shown broken away.As is conventional, a hydraulic lift cylinder 22 is provided for raisingand lowering the boom 20, by moving it about the pivot 18. At its outerend, boom 20 carries a workman's platform 24, and it will be understoodthat all movements may be controlled from workmans platform 24,including specifically the raising and lowering of boom 20, the rotationof boom and boom support 16 about the axis A and the extension andretraction of boom 20. 5

Referring now to FIG. 2, there is shown an enlarged view of the chassisl4. Chassis 14 comprises a front chassis member 32 which extendstransversely, chassis member 32 being shown in FIG. 3 to be an I-beam.At the rear, there is a rear transversely extending chassis member 34,which has the cross sectional shape of a channel. Forwardly of the rearchassis member 34 are a pair of rear auxiliary chassis members 36 and38, also having a channel shaped cross section A pair of transverselyspaced longitudinally extending integral chassis members andcounterweights 40 and 42 may be seen in FIG. 2, extending between thefront chassis member 32 and the rear chassis member 34. The auxiliarychassis members 36 and 38 may be seen extending from and connected tothe longitudinally extending chassis members 40 and 42, respectively,being welded thereto. Extending at an angle between the front chassismember 32 and the longitudinal chassis members 40 and 42 are a pair ofdiagonal braces 44 and 46, and a similar pair of rear diagonal braces 48and 52 extend between the longitudinal chassis members 40 and 42 and theauxiliary chassis members 36 and 38.

A front intermediate transverse member 54 and a rear intermediatetransverse member 56 are provided, extending between and joined to thelongitudinal chassis members 40 and 42, as by welding. The parallelmembers 54 and 56 are spaced apart approximately the same distance asthe members 40 and 42, and each lies the same distance from thefront-to-rear center of the chassis 14. Supported on the members 40, 42,54 and 56 which have their upper surfaces substantially coplanar, is acylinder 58 having a plurality of radially extending plates 60 joined toand extending inwardly from the inner wall thereof. The diameter ofcylinder 58 is substantially the same as the distance between membersand 42, and members 54 and 56. The cylinder 58 and plates 60 serve tosupport a horizontal ring 62 having its axis and that of the cylinder 58coextensive, and designated A. As will be readily understood, the ring62 may support a hearing, or the like, so that the boom supportstructure 16 may rotate thereon, about the axis A. Due to thepositioning of the members 54 and 56, the axis A is at the front-to-rearcenter of chassis 14.

There is shown in FIG. 4 a cross sectional view of the longitudinallyextending chassis member 40. This is a vertical cross section, and asmay be seen therefrom, the chassis member 40 is rectangular in verticalcross section, having the long side thereof extending in the verticaldirection. In practice, the members 40 and 42 are metal slabsapproximately two and one half inches in width and approximatelyfourteen inches in depth. As a consequence, these longitudinal chassismembers 40 are of far greater strength than is required for normalstress considerations of the apparatus 10. However, due to the greatweight of the members 40 and 42, they also serve as counterweights, tocounteract tipping moments, such as those occurring when the boom 20lies in a plane which extends generally perpendicularly to thelongitudinal axis of the chassis 14. The longitudinally extendingmembers 40 and 42 are preferably of uniform size and cross sectionalshape throughout their lengths, although as will be understood, theother members may be joined or connected to them, as illustrated in thedrawing, and in addition there may be a requirement that there be anoccasional discontinuity in one or both of these members, such as thehole 64 in the member 40.

By making the chassis members 40 and 42 of metal slabs, greater economyis achieved than where rolled steel sections are utilized, andcounterweights are bolted or otherwise secured to them.

There has been provided an improved aerial platform apparatus whereinlongitudinally extending chassis members function as both stresstransmitting members and counterweights, transferring stresses from theboom and boom suppport structure to the ground engaging wheels, throughother chassis members. The longitudinally extending chassis members areof substantially greater size than is normally required for conventionalstress considerations, the extra size being provided in order to providean integral counterweight and chassis member.

It will be obvious to those skilled in the art that various changes maybe made without departing from the spirit of the invention, andtherefore the invention is not limited to what is shown in the drawingsand described in the specification but only as indicated in the appendedclaims.

I claim:

1. Aerial platform apparatus comprising:

a. a chassis and ground engaging wheels supporting said chassis;

b. said chassis comprising:

i. a pair of longitudinally extending chassis members, each being aunitary, integral slab of metal having a vertical rectangular crosssection;

ii. front and rear transversely extending chassis members joined to saidlongitudinally extending chassis members adjacent the ends thereof; and

iii. front and rear intermediate transverse members extending betweensaid longitudinally extending chassis members spaced apart approximatelythe same distance as said longitudinally extending chassis members andlying adjacent the longitudinal center of said chassis;

c. cylindrical support means extending upwardly from and supported onboth said longitudinally extending members and both said intermediatetransverse members, said cylindrical support means having a diametersubstantially the same as said distance between said members, d.rotatable boom support means on said cylindrical support means, arid e.a boom carried by said boom support means and having a platform on theouter end thereof.

2. The aerial platform apparatus of claim I, wherein said boom ispositionable to extend transversely of the longitudinally extendingmembers, whereby a tipping moment is generated about an axis parallel tothe longitudinal axis of the chassis and is counterbalanced by a saidlongitudinally extending chassis member.

3. The aerial platform apparatus of claim 2, wherein said boom isextensible.

4. The aerial platform apparatus of claim 3, said chassis furthercomprising diagonal braces extending from said longitudinally extendingmembers.

5. The aerial platform apparatus of claim 1, said chassis furthercomprising diagonal braces extending from said longitudinally extendingmembers.

6. The aerial platform apparatus of claim 1, said intermediatetransverse members having upper surfaces 5 substantially coplanar withupper surfaces of said longi-

1. Aerial platform apparatus comprising: a. a chassis and groundengaging wheels supporting said chassis; b. said chassis comprising: i.a pair of longitudinally extending chassis members, each being aunitary, integral slab of metal having a vertical rectangular crosssection; ii. front and rear transversely extending chassis membersjoined to said longitudinally extending chassis members adjacent theends thereof; and iii. front and rear intermediate transverse membersextending between said longitudinally extending chassis members spacedapart approximately the same distance as said longitudinally extendingchassis members and lying adjacent the longitudinal center of saidchassis; c. cylindrical support means extending upwardly from andsupported on both said longitudinally extending members and both saidintermediate transverse members, said cylindrical support means having adiameter substantially the same as said distance between said members,d. rotatable boom support means on said cylindrical support means, ande. a boom carried by said boom support means and having a platform onthe outer end thereof.
 2. The aerial platform apparatus of claim 1,wherein said boom is positionable to extend transversely of thelongitudinally extending members, whereby a tipping moment is generatedabout an axis parallel to the longitudinal axis of the chassis and iscounterbalanced by a said longitudinally extending chassis member. 3.The aerial platform apparatus of claim 2, wherein said boom isextensible.
 4. The aerial platform apparatus of claim 3, said chassisfurther comprising diagonal braces extending from said longitudinallyextending members.
 5. The aerial platform apparatus of claim 1, saidchassis further comprising diagonal braces extending from saidlongitudinally extending members.
 6. The aerial platform apparatus ofclaim 1, said intermediate transverse members having upper surfacessubstantially coplanar with upper surfaces of said longitudinallyextending chassis members.
 7. The aerial platform apparatus of claim 6,wherein said intermediate transverse members are structural sections.